For example, a vehicle having an engine and an electric motor for driving has been known. In the vehicle, an engine coolant is heated by an electric heating device to lower a threshold of water temperature under which an engine is turned ON to meet a water temperature requirement for air heating. As a result, an engine stop frequency increases to improve a fuel economy.
In addition, in a technique disclosed in Patent Document 1, in a hybrid vehicle having a first heating system using an engine as a heat source and a second heating system using an electric energy of a battery as a heat source, one of the first heating system and the second heating system is selected to perform heating so as to minimize a consumption energy (fuel consumption) based on a travel request and a heating request.